of North America
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of North America
May 1 998
Prepared in cooperation with
The Nature Conservancy and the
U.S. Geological Survey
Robert G. Bailey, 1 Geographer
Ecosystem Management Coordination Staff
USDA Forest Service, Washington, DC
' Address: Ecosystem Management Analysis Center, USDA Forest Service,
3825 East Mulberry Street, Fort Collins, CO 80524 USA.
Bailey, Robert G. 1998. Ecoregions map of North America:
Explanatory note. Misc. Publ. 1548. Washington, DC:
USD A Forest Service. 10 p.
This publication explains the basis of map units shown
on the second (revised) edition of the map, Ecoregions
of North America (Bailey 1997). Climate diagrams are
included to help explain the conditions that create a
particular ecoregion. The revised map at a scale of
1:15.000.000 accompanies this explanatory note.
Keywords: ecosystem geography, ecoregions, North America
I am indebted to John M. Crowley, who began the task of
classifying the natural ecosystems of the continent and their
distribution. Recognition should also go to Denny Gross-
man. Chief Ecologist of The Nature Conservancy, for his
support. The first draft of the map was made by Jon Havens
of LCT Graphics. I am most grateful to the U.S. Geological
Survey, which helped fund the preparation of the base map.
As always, it has been a pleasure to work with Loreen Utz
and Dave Dee of the National Mapping Division of the Sur-
vey, who did the final map compilation and cartography.
Ecoregions Map of North America: Explanatory Note
Land management is undergoing enormous change: away from managing single
resources to managing ecosystems. An ecosystem is an area, of any size, in which
there is a distinctive association of causally interconnected features. A change in one
feature causes a change within another with corresponding geographic distribution, as
when certain vegetation and soil types occur together with certain types of climate. To
manage ecosystems we must understand where they are located and why. We need to
do this at multiple scales because ecosystems occur in a hierarchy of varying sizes.
Ecosystems of regional extent, those at the macro scale, are called ecosystem regions,
or ecoregions. Ecoregions are useful in addressing environmental issues over large
areas, i.e., issues that transcend agency, watershed, and political boundaries and
borders, such as air pollution, declining anadromous fisheries, forest disease, or
threats to biodiversity.
The second (revised) edition of the map, Ecoregions of North America (Bailey 1997),
is the result of cooperation among the USDA Forest Service, The Nature Conservan-
cy, and the U.S. Geological Survey. The first edition of the map was
published in 1981 by the U.S. Fish and Wildlife Service (Bailey and Cushwa 1981).
Since that time, more ecological mapping has been earned out in some parts of the
continent (e.g., Dinerstein and others 1995) and new or updated national maps have
been compiled (e.g., Ecoregions Working Group 1989: Bailey 1994, 1995); it was
therefore decided that a second revised edition of the map should be published. It has
been compiled from a number of sources, both new since 1981 and older; the most
important of which are listed in the Sources.
The map uses a worldwide classification developed by Bailey (1983, 1989. 1998) and
Bailey and Hogg (1986) from concepts advanced by Crowley (1967). The general
principle followed has been to identify ecosystem regions of continental scale based
on macroclimate (i.e., the climate that lies just beyond the local modifying irregulari-
ties of landform and vegetation). Macroclimates are among the most significant
factors affecting the distribution of life on earth. As the macroclimate changes, the
other components of the ecosystem change in response. Macroclimates influence soil
formation and help shape surface topography, as well as affecting the suitability of a
given system for human habitation. As a result, ecosystems of different macroclimates
Based on macroclimatic conditions and on the prevailing plant formations determined
by those conditions, I subdivided the continent into ecoregions with three levels of
detail. Of these the broadest, domains, and within them divisions, are based largely on
the broad ecological climate zones of W. Koppen (as modified by Trewartha 1968,
Appendix 1). : Thermal and moisture limits for plant growth determine their
2 Other methods for mapping zones at the global scale are those of Thornthwaite (1931, 1933). Holdridge (1947). and
Walter and Box (1976). All methods appear to work better in some areas than in others, and to have gained their own
adherents. I chose the Koppen system as the basis for ecoregion delineation because it has become the international
standard for geographical purposes.
boundaries. Domains are groups of related climates. There are four groups. Three are
humid, thermally differentiated: polar, with no warm season; humid temperate, rainy
with mild to severe winters; humid tropical, rainy with no winters. The fourth, dry, is
defined on the basis of moisture alone, and transects the otherwise humid domains.
Within these groups are 15 types of climate based on seasonality of precipitation or
on degree of dryness or cold, e.g., within the humid tropical domain, rainforests with
year-round precipitation can be distinguished from savannas with winter drought.
Divisions correspond to these types. Each division is clearly defined by a particular
type of climate diagram that helps explain the conditions that create them (see Appen-
dix 2 for stations thought to be representative of each division). For more informa-
tion, including illustrated, detailed descriptions of the divisions, see my
related book, Ecoregions (Bailey 1998).
The climate is not completely uniform within divisions, so that a further subdivision
can be undertaken. Within the dry climates, for example, there is a wide range of
degree of aridity, ranging from very dry deserts through transitional levels of aridity
in the direction of adjacent moist climates. We refer to these as climate subtypes. The
subtypes largely correspond to major plant formations (for example, broadleaved
forest), which are delimited on the basis of macro features of the vegetation by
concentrating on the life-form of the plants. They form the basis for subdividing
ecoregion divisions into provinces, and are based on a number of sources, including
a world map of landscape types (Milanova and Kushlin 1993).
The arrangement of the ecological climate zones depends largely on latitude and
continental position. This pattern, however, is overlain by mountain ranges, which cut
across latitudinally oriented climatic zones to create their own ecosystems. Altitude
creates characteristic ecological zones that are variations of the lowland climate.
Mountains show typical climatic characteristics, depending on their location in the
overall pattern of global climatic zones. The mountain ranges of Central America, for
example, experience the same year-round, high-energy input, and seasonal moisture
regime consisting of a relatively dry winter and rainy summer typical of their neigh-
boring lowlands (see the diagrams for Mexico City and San Salvador in Appendix 2).
Every mountain within a climatic zone has a typical sequence of altitudinal belts,
with different ecosystems at successive levels: generally montane, alpine, and nival,
but exhibiting considerable differences according to the zone where they occur. When
a mountain extends over two or more climatic zones it produces different vertical
zonation patterns. Mountains exhibiting altitudinal zonation and the climatic regime
of the adjacent lowlands are distinguished according to the character of the zonation
by listing the altitudinal zones present. Such mountainous environments are termed
Thirty-four provinces and 29 mountain provinces are differentiated and represented
on the present map (within 15 divisions and four domains).
Note that these ecoclimatic zones are greatly simplified and do not show soil-related
or human influences. The only major exception is where intrazonal contrasts (related
to groundwater) form riverine forests along the lower Mississippi River valley. Also,
the boundaries shown are only approximate and give a broad-brush picture. The actual
boundaries may be very irregular and much modified by human interference.
The similar colors on the map show the major climatic zones: the mountains in each
zone are shown by pattern. The names of the provinces retain the names of the most
obvious vegetation indicator: tundra, broadleafed forest, etc. The terms used in
describing the provinces may not be familiar and so need explanation. They are listed
in the Glossary. In mountain areas, the altitudinal zonality-types are named from the
lower- and upper-elevation (subnival) belts: (e.g., forest - alpine meadow), which vary
considerably according to the zones in which they occur. Each type corresponds to a
typical sequence of altitudinal belts.
When it is necessary to emphasize the existence of intermediate belts in the structure
of similar spectra, the name of the most characteristic intermediate belt is added to
the designation; for example, mixed forest - coniferous forest - tundra. In low- and
medium-relief mountains, the zonal spectra are incomplete. In such cases, the type is
designated by the character of the lower belt. More details are presented elsewhere
(Bailey 1983, 1996).
A digital version of the map is available in ARC/INFO format from the USDA-Forest
Service, Ecosystem Management Analysis Center, on a cost-of-production basis.
Broadleafed — with leaves other than linear in outline: as
opposed to needleleafed or grass-like (graminoid).
Coniferous — trees bearing cones and commonly having
needleshaped leaves usually retained during the year;
adapted to moisture deficiency due to frozen ground or
soils that are not moisture-retentive.
Deciduous — woody plants, or pertaining to woody plants, that
seasonally lose all their leaves and become temporarily
Desert — supporting vegetation of plants so widely spaced.
or sparse, that enough of the substratum shows through to
give the dominant tone to the landscape.
Dry steppe — with 6-7 arid months in each year.
Evergreen — plants, or pertaining to plants, which remain
green in parts of the year around, either by retaining at least
some of their leaves at all times, or by having green stems
which carry on the principal photosynthetic functions.
Forest — open or closed vegetation with the principal layer
consisting of trees averaging more than 5 m in height.
Forest-steppe — intermingling of steppe and groves or strips
Forest-tundra — intermingling of tundra and groves or strips
Heath — an area of largely treeless country, dominated by
various grasses able to thrive on poor acidic soils, often
accompanied by dwarf shrubs.
Meadow — closed herbaceous vegetation, commonly in
stands of rather limited extent, or at least not usually
applied to extensive grasslands.
Mixed forest — forest with both needleleafed and
Nival — of or relating to a region of perennial snow.
Open woodland (also called steppe forest and woodland-
savanna) — open forest with lower layers also open,
having the trees or tufts of vegetation discrete but
averaging less than their diameter apart.
Paramo — the alpine belt in the wet tropics.
Prairie — consist of tall grasses, mostly exceeding 1 m in
height, comprising the dominant herbs, with subdomi-
nant forbs (broadleafed herbs).
Riverine forest (also called galeria and floodplain forest) —
dense tropical, subtropical, or prairie, forest living along
the banks of a river.
Savanna — closed grass or other predominantly herbaceous
vegetation with scattered or widely-spaced woody plants
usually including some low trees.
Semidesert (also called half-desert) — is an area of
xerophytic shrubby vegetation with a poorly-developed
herbaceous lower layer, e.g., sagebrush.
Semi-evergreen forest (also called a monsoon forest) —
where many, although not all, of the trees lose their
leaves; adaptation to a dry season in the tropics.
Shrub — a woody plant less than 5 m high.
Steppe (also called shortgrass prairie) — open herbaceous
vegetation, less than 1 m high, with the tufts or plants
discrete, yet sufficiently close together to dominate the
Tayga (also spelled taiga) — a parkland or savanna with
needleleafed (usually evergreen) low trees and shrubs.
Tundra — slow-growing, low-formation, mainly closed
vegetation of dwarf-shrubs, graminoids. and cryp-
tograms, beyond the subpolar or alpine tree-line.
The sources listed below have been consulted during the
process of creating and updating the second edition.
Bailey, R.G. 1983. Delineation of ecosystem regions. Envi-
ronmental Management 7: 365-373.
Bailey, R.G. 1989. Explanatory supplement to ecoregions
map of the continents. Environmental Conservation
16:307-309 with separate map at 1:30,000,000.
Bailey, R.G. 1994. Map: Ecoregions of the United States
(rev.). Washington, DC: USDA Forest Service.
Bailey, R.G. 1995. Description of the ecoregions of the Unit-
ed States. 2d ed. rev. and expanded (1st ed. 1980). Misc.
Publ. 1391 (rev.). Washington, DC: USDA Forest Ser-
vice. 108 p. with separate map at 1:7.500.000.
Bailey, R.G. 1996. Ecosystem geography. New York:
Springer- Verlag. 216 p.
Bailey, R.G. 1997. Map: Ecoregions of North America
(rev.). Washington, DC: USDA Forest Service in coopera-
tion with The Nature Conservancy and the U.S. Geologi-
cal Survey. 1:15,000,000.
Bailey. R.G. 1998. Ecoregions: the ecosystem geography of the
oceans and continents. New York: Springer- Verlag. 192 p.
Bailey, R.G.; Cushwa, C.T 1981. Map: Ecoregions of North
America. FWS/OBS-81/29. Washington, DC: U.S. Fish
and Wildlife Service. 1:12,000,000.
Bailey, R.G.; Hogg, H.C. 1986. A world ecoregions map
for resource reporting. Environmental Conservation
Borchert, J.F. 1950. The climate of the central North Ameri-
can grassland. Annals Association of American Geogra-
Cleland. D.T.; Avers, P.E.; McNab, W.H.; Jensen, M.E.: Bai-
ley, R.G.; King, T.; Russell, W.E. 1997. National
hierarchical framework of ecological units. In: Boyce,
M.S.; Haney, A., eds. Ecosystem management. New
Haven. CT: Yale University Press: 181-200.
Crowley, J.M. 1967. Biogeography [in Canada]. Canadian
Geographer 11: 312-326.
Dinerstein, E.; Olson, D.M.; Graham, D.J.; Webster, A.L;
Primm, S.A.; Bookbinder. M.P; Ledec, G. 1995. A
conservation assessment of the terrestrial ecoregions of
Latin America and the Caribbean. Washington, DC: The
World Bank in association with The World Wildlife Fund.
129 p. with separate map at 1:15,000.000.
Ecoregions Working Group. 1989. Ecoclimatic regions of
Canada, first approximation. Ecological Land Classif.
Series No. 23. Ottawa: Environment Canada. 119 p. with
separate map at 1:7,500,000.
Ewel, J.J.; Whitmore, J.L. 1973. The ecological life zones of
Puerto Rico and the U.S. Virgin Islands. Forest Service
Research Paper ITF-18. Rio Piedras, PR: Institute of
Tropical Forestry. 72 p. with separate map at 1 :250,000.
Eyre, S.R. 1963. Vegetation and soils: a world picture.
Chicago: Aldine. 324 p.
Fosberg. F.R.; Gamier, B.J.: Kuchler, AW. 1961. Delimita-
tion of the humid tropics. Geographical Review 51:333-
347 with separate maps at 1:60.000,000.
Government of Canada. 1974. National atlas of Canada,
vegetation regions. 4th ed. (rev.). Toronto: Macmillan:
45-46. In association with the Department of Energy,
Mines and Resources, and Information Canada, Ottawa.
Hammond, E.H. 1954. Small-scale continental landform
maps. Annals Association of American Geographers.
Holdridge, L.R. 1947. Determination of world plant forma-
tions from simple climatic data. Science 105:367-368.
Koppen, W. 1931. Grundriss der klimakunde. Berlin: Walter
de Gruyter. 388 p.
Kuchler, A.W. 1964. Potential natural vegetation of the con-
terminous United States (map and manual). American
Geographical Society Special Publication 36. 116 p. with
separate map at 1:3,168,000.
Lobeck, A.K. 1948. Map: Physiographic provinces of North
America. Maplewood NJ: Hammond. 1:12.000,000.
Milanova, E.V.; Kushlin, A.V.. eds. 1993. World map of pre-
sent-day landscapes: an explanatory note. Moscow:
Moscow State University. 33 p. with separate map at
Rowe, J.S. 1972. Forest regions of Canada. Canadian
Forestry Service Publ. No. 1300. 172 pp. with separate
map at 1:6,336.000.
Schmithtisen, J. 1976. Atlas zur biogeographie. Mannheim-
Wien-Zurich: Bibliographisches Institut. 33 p.
Shelford, V.E. 1963. The ecology of North America. Urbana:
University of Illinois Press. 610 p.
Thornthwaite, C.W. 1931. The climates of North America
according to a new classification. Geographical Review
21:633-655 with separate map at 1:20.000.000.
Thornthwaite. C.W. 1933. The climates of the Earth. Geo-
graphical Review 23:433-440 with separate map at
Trewartha, G.T. 1968. An introduction to climate. 4th ed.
New York: McGraw-Hill. 408 p.
Udvardy, M.D.F. 1975. A classification of the biogeographi-
cal provinces of the world. Occasional Paper No. 18.
Morges, Switzerland: International Union for Conserva-
tion of Nature and Natural Resources. 48 p.
Walter. H.: Box. E. 1976. Global classification of natural
terrestrial ecosystems. Vegetatio 32:75-81.
Walter. H.: Harnickell. E.; Mueller-Dombois. D. 1975. Cli-
mate-diagram maps of the individual continents and the
ecological climate regions of the Earth. Berlin: Springer-
Verlag. 36 pp. with 9 maps.
Walter. H.: Lieth. H. 1960-1967. Klimadiagramm Weltatlas.
Jena. East Germany: G. Fischer Verlag. maps, diagrams,
profiles. Irregular pagination.
Appendix 1: Ecological climate zones"
Koppen group and types
A Tropical and humid climates
Tropical wet (Ar)
Tropical wet-dry (Aw)
Humid tropical domain (400)
Rainforest division (420)
Savanna division (410)
B Dry climates
Tropical/subtropical semi-arid (BSh)
Tropical/subtropical arid (BWh)
Temperate semi-arid (BSk)
Temperate arid (BWk)
Dry domain (300)
Tropical/subtropical steppe division (310)
Tropical/subtropical desert division (320)
Temperate steppe division (330)
Temperate desert division (340)
C Subtropical climates
Subtropical dry summer (Cs)
Humid subtropical (Cf)
D Temperate climates
Temperate oceanic (Do)
Temperate continental, warm summer (Dca)
Temperate continental, cool summer (Deb)
Humid temperate domain (200)
Mediterranean division (260)
Subtropical division (230)
Prairie division (250) b
Marine division (240)
Hot continental division (220)
Prairie division (250) b
Warm continental division (210)
Prairie division (250) b
E Boreal climates
Polar domain (100)
Subarctic division (130)
F Polar climates
Ice Cap (Fi)
Tundra division (120)
Icecap division (110)
Definitions and Boundaries of the Kbppen-Trewartha System
Ar All months above 18°C and no dry season.
Aw Same as Ar, but with 2 months dry in winter.
BSh Potential evaporation exceeds precipitation, and all months above 0°C.
BWh One-half the precipitation of BSh, and all months above 0°C.
BSk Same as BSh, but with at least 1 month below 0°C.
BWk Same as BWh, but with at least 1 month below 0°C.
Cs 8 months 10°C, coldest month below 18°C, and summer dry.
Cf Same as Cs, but no dry season.
Do 4 to 7 months above 10°C, coldest month above 0°C.
Dca 4 to 7 months above 10°C, coldest month below 0°C, and warmest month above 22°C.
Deb Same as Dca, but warmest month below 22°C.
E Up to 3 months above 10°C.
Ft All months below 10°C.
Fi All months below 0°C.
A/C boundary = Equatorial limits of frost; in marine locations, the isotherm of 18°C for coolest month.
C/D boundary = 8 months 10°C.
D/E boundary = 4 months 10°C.
E/F boundary = 10°C for warmest month.
B/A, B/C, B/D. B/E boundary = Potential evaporation equals precipitation.
Based on the Koppen system of classification (1931). as modified by G.T. Trewartha ( 19681.
Koppen did not recognize the Prairie as a distinct climatic type. The ecoregion classification
system represents it at the arid sides of the Cf. Dca, and Deb types, following Borchert ( 1950).
Appendix 2: Climate diagrams of representative climate stations (based on Walter and Lieth 1960-67, Walter and others 197
Eismitte, Greenland (3030 m)
Barrow, Alaska (4 m)
-12.2 C C 104 mm
Ft Vermilion, Alberta (290 m)
-1.8°C 323 mm
Aishihik (966 m)
-3.6°C 248 mm
M220 Hot Continental
BoonejM. Carolina. ^(1016m)
Fargo, N. Dakota (273 m)
4.9°C 476 mm
Humid Temperate Domain r
210 Warm Continental
Duluth, Minnesota (354 m)
3.4°C /\ 755 mm
Atlanta^Georgia (297 m)
J r MAMJJASOND
Pasadena, California (263 m)
220 Hot Continental
Ft. Wayne, Indiana (244 m)
9.9°C 869 mm
^Vancouver, British Columbia (8 rcj^"
"~~\10.0°C 1050 mm f~
i i i i i i i i i i
Jahoe, California (1900 m)
J — MAMJJASOND
Abilene, ATexas (534 m]
18.1°C /\ 622 mm
_! I 1 1 I I L_
M330 Temperate Steppe
Pikes Peak, Colorado (4301 m)
-7.0°C y\ P\ 752 mm
Brawley, California (-36 m)
22.0°C 58 mm
340 Temperate Desert
Salt Lake City, Utah (1300 m)
10.6°C 414 mm
330 Temperate Steppe
Colorado Springs, Colorado (1855 m)
8.7°C 363 mm
Humid Tropical Domain
San Salvador, El Salvador (698 m)
23.2°C _ 1770 mm
Mexico City, Mexico (2280 m)
15.6°C 588 mm
Belize, Belize (5 m)
29.5°C 1810 mm
I I I I I
Mean annual temp. Mean annual pptn.
Relative period __
of drought -y£ ^s< ^
F M A M J J A S N
North America Ecoregions Map
The USDA Forest Service recently published a revised version of the ecoregions
map of North America by Robert G. Bailey in cooperation with The Nature
Conservancy and the U.S. Geological Survey. This 29" x 32" full-color map shows,
at a scale of 1:15,000,000, the division of the continent into a hierarchy of ecosystem
regions. The map replaces the now outdated map of North America ecoregions
which was issued in 1981 by the U.S. Fish and Wildlife Service. The revised map
can be used to address environmental issues that transcend agency, watershed, and
political boundaries and borders.
Part of Ecoregions Map of North America, 1997 edition. Source scale 1:15,000,000
-v (r Mil
For a/ree copy, write the author at:
USDA Forest Service
3825 East Mulberry Street
Fort Collins, Colorado 80524 USA
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U.S. DEPARTMENT OF AGRICULTURE
FOREST SERVICE eo°
| no | Icecap
1 120 | Tundra
[ 130 | Subarctic /
1 210 | Warm Continental
I 220 | Hot Continental
I 230 | Subtropical
I 240 | Marine
I 250 | Prairie
1 260 1 Mediterranean
1 310 | Tropical/Subtropical Steppe
| 320 | Tropical/Subtropical Desert
j 330 1 Temperate Steppe
j 410 Savanna
| 420 | Rainforest
Mountains with altitudinal zonation
Base from World Databank II
Prepared by the U.S. Geological Survey
ECOREGIONS OF NORTH AMERICA
By Robert G. Bailey
U.S. Department of Agriculture, Forest Service
Jointly supported by the U.S. Forest Service and
The Nature Conservancy, Conservation Science Division
INTERIOR - GEOLOGICAL SURVEY. RESTON. VA • 1998
Representative climate station
Boundary of domain
Boundary of division
Boundary of province
100 POLAR DOMAIN
110 ICECAP DIVISION
in Glacial ice
120 TUNDRA DIVISION
I i2i | Ice and stoney deserts
| 122 I Arctic tundras
| 123 | Tundras
Ml 2 TUN DRA MOUNTAINS
KM12M Polar desert
Tundra - polar desert
j/M 123/1 Tundra - meadow
['Ml 2jt| Oceanic meadow - heath
130 SUBARCTIC DIVISION
| i3i j Forest-tundras and open woodlands
| 132 | Tayga (boreal forests)
Ml 30 SUBARCTIC MOUNTAINS
^mbi^J Open woodland - tundra
[Mi32a^| Tayga - tundra, medium
I'M 132b 1 ] Tayga - tundra, high
200 HUMID TEMPERATE DOMAIN
210 WARM CONTINENTAL DIVISION
I 2ii | Mixed deciduous-coniferous forests
M210 WARM CONTINENTAL MOUNTAINS
[M2iia] Mixed forest - coniferous forest - tundra, medium
^M2iibj Mixed forest - coniferous forest - tundra, high
220 HOT CONTINENTAL DIVISION
Broadleaved forests, oceanic
Broadleaved forests, continental
M220 HOT CONTINENTAL MOUNTAINS
[M22i/| Deciduous or mixed forest - coniferous forest - meadow
|^M222J Broadleaf forest - meadow
230 SUBTROPICAL DIVISION
231 Broadleaved-coniferous evergreen forests
I 232 Coniferous-broadleaved semi-evergreen forests
M230 SUBTROPICAL MOUNTAINS
LM23n Mixed forest - meadow
i / / /I
240 MARINE DIVISION
241 Mixed forests
M240 MARINE MOUNTAINS
iMMi'j Deciduous or mixed forest - coniferous forest - meadow
[M242a] Forest - meadow, medium
^M242bi Forest - meadow, high
250 PRAIRIE DIVISION
| 251 \ Forest-steppes and prairies
I 252 | Prairies and savannas
260 MEDITERRANEAN DIVISION
| 261 j Dry steppe
| 262 | Mediterranean hardleaved evergreen forests, open woodlands and shrub
I 263 \ Redwood forests
M260 MEDITERRANEAN MOUNTAINS
[M26i^ Mixed forest - coniferous forest - alpine meadow
yM262y\ Mediterranean woodland or shrub - mixed or coniferous forest - steppe or meadow
Shrub or woodland - steppe - meadow
300 DRY DOMAIN
310 TROPICAL/SUBTROPICAL STEPPE DIVISION
| 3ii j Coniferous open woodland and semideserts
j 312 I Steppes
| 313 j Steppes and shrubs
| 314 Shortgrass steppes
M310 TROPICAL/SUBTROPICAL STEPPE MOUNTAINS
[-mmi^ Steppe or semidesert - mixed forest - alpine meadow or steppe
320 TROPICAL/SUBTROPICAL DESERT DIVISION
321 | Semideserts
j 322 | Oceanic semideserts
I 323 j Deserts on sand
M320 TROPICAL/SUBTROPICAL DESERT MOUNTAINS
Semidesert - shrub - open woodland - steppe or alpine meadow
yyup^ Desert or semidesert - open woodland or shrub - desert or steppe
330 TEMPERATE STEPPE DIVISION
| 331 I Steppes
| 332 I Dry steppes
M330 TEMPERATE STEPPE MOUNTAINS
Forest-steppe - coniferous forest - meadow - tundra
Steppe - coniferous forest - tundra
£m333^J Steppe - coniferous forest
• M33J Steppe - open woodland - coniferous forest - alpine meadow
340 TEMPERATE DESERT DIVISION
| 341 j Semideserts
I 342 | Semideserts and deserts
M340 TEMPERATE DESERT MOUNTAINS
pM341/ Semidesert - open woodland - coniferous forest - alpine meadow
400 HUMID TROPICAL DOMAIN
410 SAVANNA DIVISION
[ 411 Open woodlands, shrubs, and savannas
| 412 j Semi-evergreen forests
|^| Deciduous forests
M410 SAVANNA MOUNTAINS
fwu ^ Open woodland - deciduous forest - coniferous forest - steppe or meadow
Forest ■ steppe
420 RAINFOREST DIVISION
I 421 | Semi-evergreen and evergreen forests
M420 RAINFOREST MOUNTAINS
Evergreen forest - meadow or paramos
Mountains with altitudinal zonation. These provinces are named 101 the spectrum
of /ones from lower to upper (subnival); e.g.. semidesert coniferous forest